Enclosing a carport

[rickjames8]

Hello all,

I recently bought a 20'wide by 19'long carport with the intention of enclosing it. I'd like to post my plans here, and get comments from others on what they might do differently, or validate my ideas.

When I ordered my carport, I upgraded to the 12ga steel to support the weight of the walls I intended to put on. The carport is attached firmly to the ground with rebar in some parts, and bolts in others.

My plan is as follows:

Re-inforce the back with a 4x4 in the center of the wall (not yet built)
Re-inforce the center of the carport with a 4x4 as well
Install two 4x4s in the front, one on either side of where the 17'wide garage door would go.
All of the reinforcing would be to handle the snow, although we typically dont get much here.

Then frame out the rear wall and the front gable with aluminum 2x4's. The header bar at the top of the garage door would be wood 2x4 as it would show.

Then cover the entire thing with 7/16 OSB sheathing, using self-drilling hex-head screws and washers.

Install flashing around the base to direct water away.

Then cover all of that with vinyl siding.

I would add a vent to the top of the rear gable.

I would be adding a doors and a couple windows, framing them in using the aluminum framing.

Comments?

 

[BlackTalon]

Might consider contacting the carport manufacturer and confirming the framing system can handle the wind loads the structure will be subjected to once it gets closed in. There will be lateral loads that do not exist with the carport scheme.

 

[musgofasta]

What your considering has been done a few times and most carport manufacturers now offer them with metal wall panels.


Here's one that I have saved that did exactly what you're wanting to do:

http://www.garagejournal.com/forum/showthread.php?t=157554&highlight=carolina+carport

 

[sublimate]

Re-inforce the center of the carport with a 4x4 as well

A 4x4 post in the middle of your garage? I think you'll regret that.
If the roof can handle the snow loads as is (without walls) then it should be fine with walls. The walls will only add wind loading, and a post in the middle won't help with that.

Or is the carport as is not built for the snow loads in your area?

 

[Moose364]

I'm doing the same thing I have a 24 x 36 then a built a 11x36 down one side. everything I have done is welded in place and all metal. I have the 14g it started out only as a place to park my 2 boats and tractor, lawnmower etc. I only installed the metal u panel down the sides turned sideways I'm in the process of finishing the ends 10x10 roll up on front and 8x8 rollup on back. I have the side done all except the bottom piece of u panel, we had 80mph winds the other night with no problems, If I were you I would do the metal u panel down the sides and not the OSB board seems like a lot of extra work unless your going to heat, you can get the u panel to match your house color or real close anyway, run it sideways and it will look as good as vinyl siding. and you want have to worry about wood rot down the road

 

[kbs2244]

I would avoid the center post also.
Put a joist at the center point with a vertical up to the ridge.
Look up a “King Post” truss.
Do the same at the front and rear wall.

Put the OSB horizontal in an “brick laid,” with offset joints, pattern so you get the best in racking protection.

 

[rickjames8]

Musgofasta,

Thanks for the link. I'd seen a couple here on GJ, but not that one. I had planned to use steel studs rather than wood because I didn't think it'd be supporting much, and I thought the metal would be better for the elements than wood. However, I think if I made it from wood, I could add a little rigidity to the structure.

Sublimate,

We don't get a lot of snow here in DC. We do have the occasional 'snowmageddon' but not often. It was a poster from a previous comment I made who made me worry about the snow. So I thought as long as I am doing this work, I could spend a little extra and build some reinforcements.

I called the place I ordered the carport and they looked up my actual order and my specs are: Roof will handle 25lbs/FT and the structure (as is, no walls) will withstand 90mph winds.

 

[rickjames8]

KBS,

I had planned to go horizontal, as my walls are only 7ft high. I planned to use the 1ft strips to join the OSB together at the seams on the inside I had wondered if a brick pattern would work best. I appreciate the input!

 

[rickjames8]

As for my plan to put a support in the middle of the carport. It seems that the current structure could hold about 20" of snow, depending on the density/wetness of it. I looked up the King truss and could try to build one.

One other idea that I had: Burying a post base in the gravel, so the top is level with the gravel, and also affixing a support to the top of the ceiling and attaching a post cap to it. Then in the winter just dig out the gravel from around the base and put the 4x4 in during our snow months, which is really only a 3-4 months of the year.

 

[BlackTalon]

We don't get a lot of snow here in DC. We do have the occasional 'snowmageddon' but not often. It was a poster from a previous comment I made who made me worry about the snow. So I thought as long as I am doing this work, I could spend a little extra and build some reinforcements.

I called the place I ordered the carport and they looked up my actual order and my specs are: Roof will handle 25lbs/FT and the structure (as is, no walls) will withstand 90mph winds.

FYI for the DC area:

- 25 psf base snow load and 90 mph wind

- At the eaves and ridge, the 90 mph design wind speed will result in ~20-25 psf uplift.

- The snow load will typically be less than the 25 psf base snow load due to the roof slope; probably closer to 20 psf.

So as a carport it looks like the structure is designed just about perfect for the design loads. Adding the lateral loads from wind forces against walls is the main issue that I see. Wind + Snow would seem to be the critical load combination, especially for the columns that currently do not have to take lateral loads. There is some excess capacity, but not much. (of course this is with trying to maintain the normal factors of safety; you may be okay with reducing those since this is not really an occupied structure)

Does the manufacturer have the ability to check the structure for the effect of the wind loads once walls are installed? They may be able to do this pretty easily for you if they have computer models.

 

[rickjames8]

So I think I'm going to put off this project until spring, at least, and here's why.

Our property line runs down the center of the carport. I was able to put it up without papers because the area I live in is quite lax about things like that. (The previous owner had a carport there 10 years).

I have plans to purchase that tract of land when I'm allowed to- which may be next year or in 3 years - the land is not currently for sale - that's a long story. When it is, I'm fairly certain I will be able to buy it.

But because it straddles 2 plots, I can't get a permit for it. Which means it's not legal. My wifes car (the only one with a loan) is always under there. If I modify the structure, and snow and wind push it over and crushes the car, then I'm sure the insurance company will deem me negligent and not pay out. Even with the carport as-is, there's a chance they may not pay out, however, being able to prove it's been spec'd to our weather requirements may help in my case. Showing that I modified it would almost guarantee that I'd be out of pocket $20k.

So it will remain a carport until such time that I can buy the land, and have an engineer help design it to code.

Sorry for the false alarm, but many thanks to the people who pointed out the porential risks involved with lateral wind loads, something I'd not previously considered.

-Rick

 

[Zeke]

If insurance coverage is your worry, call them and ask what is covered. No sense in trying to 2nd guess what is written in stone.

Also, you mentioned that "I upgraded to the 12ga steel to support the weight of the walls I intended to put on." The walls don't hang off the structure. They should be on a bottom plate anchored to the ground. I don't know what is on the ground at the perimeter but at the very least you should have a couple rows of block grouted solid with steel and anchors. Your carport won't blow away or blow down. I think I'd use sliding doors so as to not complicate framing for the overhead tracks. However, it may very well be quite possible to hang tracks and have enough support for the door in the open position. Just remember, that adds a small amount to the roof load in specific areas.

You also mentioned AL studs. Did you mean light ga. metal studs? Easy to work with and pretty strong when sheathed as you intend. From your post I think you are not too well versed in construction. Coming here for a discussion is a good idea. Others will follow with more suggestions.

 

[sublimate]

Our property line runs down the center of the carport. I was able to put it up without papers because the area I live in is quite lax about things like that.

Does your neighbor not mind that you built on his property, or not know?

 

[G McKay]

I wouldn't do anything without written permission from your neighbor if the carport sits on the property line. And you might get problems from the next neighbor who moves in.

Then if you get permission to do it, I would just have the company who installed it come back and just screw the same siding on the sides that is on the roof. That is what those type of buildings are built for. You can choose from many colors. And one piece will cover the side completely.


They just start at the bottom and screw 19 feet long siding up the side. They overlap each other to keep them from leaking.

If you want, you can frame up the inside with 2X4s to put in a walk thru door. The company makes roll up doors which will fit perfectly for the building. But the side walls have to be eight feet tall to have roll up doors which are seven feet tall.

If you want to, you can frame up the inside and then put up walls on the inside with whatever type of siding you want. That is the way I would do it if it were me.

 

[G McKay]

And in case you are wondering, that type of building should handle 3 feet of snow on the roof before you have any problems.

 

[BlackTalon]

I have never heard of a building code that specifies a depth of snow. The IBC, IRC and local codes have minimum 'ground snow load' requirements (in psf), and you then go through calcs for drifting snow, snow falling from adjacent higher roofs, etc. that may raise the requirement above the ** psf ground load.

 

[rickjames8]

Sublimate- The property that it straddles is a road. It's a community built in the 1930's and some tracts were designated as future roads, but never built. This is one of those tracts. It's owned by the HOA who sells the plots from time to time, but due to some administrative issues, they are not selling any plots now. They are aware the carport sits there, but don't publicly state their awareness, if that makes sense. If a resident goes to them and points out that my structure straddles the line and files a complaint, they will have to ask me to take it down. We do have those types of people in our community, they just don't live near me.

Zeke- You are corect about my lack of experience. I've done a fair amount of interior framing with wood, but nothing load bearing or exterior. However, I've ended up getting quite good at building (drwalling, flooring, plumbing, electric, woodworking, etc) by learning from forums like this, so I'm confident I'll be able to tackle this once I know it's safe. The studs I considered using were going to be steel, now that I look at them. The structure just sits on the gravel of the driveway. There is no block. It is anchored in with 30" rebar. I did plan to attach the walls directly to the frame of the stucture, adding wood or steel studs between the frame of the structure. Would you do it differently? There is a metal frame which runs the lenght of the base. The frames-within-a-frame were simply going to sit on top of a footer which sat on the metal rail.

G McKay- I didn't order the steel sides simply because I didn't like the industrial look of them. I was hoping to have something which looked a little more garage-like than shed-like.

 

[Zeke]

Sublimate- The property that it straddles is a road. It's a community built in the 1930's and some tracts were designated as future roads, but never built. This is one of those tracts. It's owned by the HOA who sells the plots from time to time, but due to some administrative issues, they are not selling any plots now. They are aware the carport sits there, but don't publicly state their awareness, if that makes sense. If a resident goes to them and points out that my structure straddles the line and files a complaint, they will have to ask me to take it down. We do have those types of people in our community, they just don't live near me.

Zeke- You are corect about my lack of experience. I've done a fair amount of interior framing with wood, but nothing load bearing or exterior. However, I've ended up getting quite good at building (drwalling, flooring, plumbing, electric, woodworking, etc) by learning from forums like this, so I'm confident I'll be able to tackle this once I know it's safe. The studs I considered using were going to be steel, now that I look at them. The structure just sits on the gravel of the driveway. There is no block. It is anchored in with 30" rebar. I did plan to attach the walls directly to the frame of the stucture, adding wood or steel studs between the frame of the structure. Would you do it differently? There is a metal frame which runs the lenght of the base. The frames-within-a-frame were simply going to sit on top of a footer which sat on the metal rail.

G McKay- I didn't order the steel sides simply because I didn't like the industrial look of them. I was hoping to have something which looked a little more garage-like than shed-like.

I understand what you intend to do. Still, the weight is on the ground, not the carport walls. Doing it 'above' ground sort of implies it's a movable structure. Unfortunately the IBC allows only a 10 x 10 foot structure max to be designated as a non permittable building. Others technically have to be built to code.

Your HOA may not know all that much and if you get a complaint the fact that you rested your foundation (don't call it a footer) on top of the ground may sway some to think it's not permanent.

Still, you should tie the blocks together in some meaningful way. Maybe use the dry stack retaining wall blocks. And you should provide some kind of anchors for the bottom track of your wall.

Any settling or heaving of the soil is going to cause you problems. You need to think this through. I don't live in snow country and have never built in snow country so maybe I ought to shut up.